Exemplary embodiments herein relate to an attenuated stopper for a seatbelt system on a vehicle.
A seatbelt system for a vehicle typically has a seatbelt retractor that serves to retract a seatbelt webbing into a housing which is attached to the vehicle body. The belt webbing is wound upon a spool rotatably supported in the housing. When the webbing is drawn out or protracted, the spool winds a retraction spring, which later retracts the unused portion of the belt webbing onto the spool or withdraws the webbing into the housing when not in use. During a crash condition, the seatbelt retractor has a lock that limits the extension of the seatbelt webbing from the housing. The lock may be actuated by an inertial sensor, which responds to changes in vehicle speed, such as those that occur during the crash. When a large deceleration is detected, the inertial sensor triggers the lock of the seatbelt retractor to secure the webbing in place during the crash.
In a locked condition, the belt webbing restrains the vehicle occupant from moving forward during a crash condition. Although the seatbelt has some give, the restraining force on the vehicle occupant can be significant. To address this force, manufacturers generally use a load limiting device, such as a torsion bar, to absorb energy from the forward movement of the vehicle occupant in a controlled manner. Consequently, the vehicle occupant is gradually slowed rather than suddenly stopped during the crash. However, torsion bars can be complex and expensive to form, and generally are not easily adaptable to different conditions, such as different vehicle characteristics, or different sizes and weights of vehicle occupants.